''I'm here under duress!'' whines the star as the cast begins its commentary. We expect nothing less from our favorite balding, bespectaled neurotic. The HBO hit, Curb Your Enthusiasm, an exercise in awkwardness and anxiety, explores the minutiae of Larry David's fictional life. The cocreator of ''Seinfeld'' demonstrates he is the master of ''nothing'' with 10 mostly improvised episodes like ''Beloved Aunt,'' in which a plot trigger may be as simple as an obituary typo, but the laughs are free-flowing. EXTRAS The kibitzing lasts only through episode 1, but the faux doc of David's attempted comedy comeback and real interview with Bob Costas make the set a must-have. As Jerry Seinfeld says, ''This guy proves you are what you are.'' We wouldn't want it any other way.